Dual stage centrifugal liquid-solids separator

ABSTRACT

Disclosed is a vortex-based centrifugal separator for removing solids from a liquid/solids fluid stream in two stages. A fluid stream under pressure is introduced at the top of the cylindrical separator at a tangential angle forming helical downward flow. The first stage uses a centrally-located spin plate for reversing the cleaner interior flow of the vortex back upward, while the heavier solids settle at the bottom of the chamber for periodic removal. In the second stage, a plurality of louvered slots in an upper discharge pipe remove finer solids from the exiting upward fluid flow prior to discharge.

This is a continuation of application Ser. No. 10/423,570 filed Apr. 24,2003 (now U.S. Pat. No. 7,025,890) which is incorporated herein by thisreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to solid-liquid separators, and moreparticularly to a new and improved device for centrifugally separatingsolids from liquids in a liquid/solid mixture in two distinct separationstages that occur during a single pass of the mixture through thedevice.

2. Description of the Prior Art

It is often desirable to separate solid particles from liquid/solidmixtures or slurries to clarify or purify the remaining liquid. Whensignificant quantities of solids are present, it is impractical to usemesh filters since they will quickly clog and be rendered useless. As aresult, centrifugal liquid-solid separators have been developed in theprior art. These devices utilize centrifugal force and gravity toachieve varying degrees of separation of solids from solid/liquidmixtures. The separated solids generally settle to the bottom of thecentrifugal chamber from which they are periodically removed.

Many existing centrifugal liquid-solid separators rely upon the rotationof an internal rotor, impeller or blades to create a centrifugal actioninside the chamber where the fluid is introduced. Unfortunately, thecentrally located rotors in such designs take up considerable spacewhich blocks much of the internal centrifugal flow.

Other existing separators utilize the general principles set forth inU.S. Pat. No. 4,072,481 which discloses a vortex system where thesolids/liquid mixture is introduced into a cylindrical chamber at atangential angle generating centrifugal action in the mixture. In thesimple separator of U.S. Pat. No. 5,622,545, a mixture of liquids andgasses is directed in a downward helical path along the internal wall ofa cylindrical chamber. A perforated separator tube is provided at thecenter of the cylinder for receiving gasses which flow toward thecenter; the gasses escape at the top, and the relatively gas-free liquidis then discharged at the bottom of the chamber. The use of a pluralityof simple vortex tubes for solid-liquid-gas-oil separation is disclosedin U.S. Pat. No. 5,827,357.

The employment of a spin plate at the bottom of a vortex tube forreversing the axial direction of flow is shown in the '481 patent above,and in U.S. Pat. Nos. 5,368,735 and 5,811,006. Both of these patentsadditionally disclose a tube leading from a quiescent region of fluidback to the vortex for re-introduction into the flow. U.S. Pat. No.6,090,276 discloses a similar but more elaborate re-introduction systemwhich includes additional filtration. In each of these inventions, theseparated liquid exits through a smaller tube provided at the top of thecylindrical chamber, and the solids settle at the bottom. The '006patent also describes turbulence reducing baffles at the bottom. Theinvention of U.S. Pat. No. 6,143,175 discloses a vortex tube separatorhaving an outer acceptance chamber having a plurality of tangentiallyoriented entrance slots through which the fluid enters the main cylinderto form the vortex.

Each of the above inventions demonstrates yet another attempt to morecompletely separate and remove solids from solid/liquid mixtures.However, as demonstrated by the many additional features found in laterinventions, complete separation in a vortex-based centrifugal system hasyet to be fully achieved.

SUMMARY OF THE INVENTION

The present invention is designed to provide improved separation andremoval of solids from a fluid stream containing a mixture of solids,liquids and gasses (the “fluid stream”) by providing two distinct stagesof separation in a single pass through the invention. In the presentinvention, the fluid stream is introduced at the top of an elongatedcylindrical chamber at a tangential angle to induce a helical flow orvortex inside the chamber. Upon introduction of the fluid stream underpressure, flow velocity is immediately increased by use of an inlet areahaving a restricted cross section, preferably parabolic in shape. Thesize of the decreased inlet area is set at a ratio corresponding to thespecific gravity of the solids to be separated out. This increase may beany suitable amount, but preferably 3.5 to 4 times the original fluidstream velocity.

As a result of the almost instantaneous increase in velocity, solids arethrown outward towards the wall of the inlet chamber by centrifugalforce, and a downwardly spiraling vortex is formed. The introduction ofthe fluid stream occurs near the top of the cylindrical chamber. At thecenter of the top of the chamber, an axially oriented tubular outlet ordischarge pipe is provided. The incoming fluid stream passes through theannular area around (outside) this pipe which, in one embodiment, isflared at its open bottom (an open bell shape) causing a pinching orcompression of the fluid stream. This squeezes air out of the streamcausing such air to travel upwards at the center. A set of air breakervanes located at the top of the chamber serve to break up and collectentrapped air bubbles, and additionally provide reinforcement to theoutlet pipe. The entrapped air bubbles are then released through anupper air relief vent.

Meanwhile, the solids-laden fluid stream continues its downward spiralaway from the center of the formed vortex. As the stream spiralsdownward in a decelerating motion, a much cleaner vortex is created atthe center of the vessel. A reversing or upper spin plate is provided inthe axial center of the chamber, reversing the cleaner flow at thecenter of the vortex, causing it to travel back upward. The higher thelocation of this upper spin plate, the less distance the fluid musttravel and the less pressure that is lost. This is where the firstseparation takes place.

The downwardly spiraling fluid stream containing the bulk of the solidspasses through the considerable annular gap between the edges of the topspin plate and the cylindrical wall of the chamber, and travels furtherdown and encounters a second spin plate having a set of angled top spinarrestor vanes attached thereto. These arrestor vanes are provided onthis lower spin plate at intervals along the interior perimeter of thecylindrical chamber, and are designed to stop the solids from spinningon top of the lower spin plate preventing any grinding wear and/ordrilling motion that the solids may contribute. An annular gap isprovided between the lower spin plate and the cylindrical chamber wallthrough which the solids are drawn down into a collection chamber. A setof baffles are provided in the collection chamber to prevent the solidsfrom further spinning and to facilitate quiescent settling of thesolids. In one embodiment, this solids collection chamber may be sizedto accommodate 3% solids content by weight in proportion to theseparator's designed flow capacity, before purging or releasing them toother conveyance periodically or continuously.

Meanwhile, the direction of the cleaner interior fluid stream isreversed above the upper spin plate so that it spirals upward in avortex at the center of the vessel. This upwardly traveling fluid streammay still contain some smaller/finer solids. Inside the top of thecylindrical chamber, a central discharge pipe is provided in axialalignment with the chamber. The upwardly traveling fluid exits theseparator through this discharge pipe. A series of louvered slots areprovided along the sides of the discharge pipe such that as the upwardlymoving fluid stream passes through the pipe, the remaining smaller/finersolids are drawn back into the main incoming stream that is swirling ina downward direction around the discharge pipe. This occurs becausethere are lesser centrifugal forces acting on the upwardly returningstream, and because of the pressure/velocity difference between theincoming stream outside of the discharge pipe and the returning streaminside the pipe. The slots are angled to the circular direction of theincoming stream. This is where the second separation takes place. Theresulting filtered discharge may be used or re-used to achieve a muchcleaner solids free requirement, and the purged solids are separated andeffectively collected.

This dual stage centrifugal separation provided by the presentinvention, with the provision of the top elevated spin plate, the angledtop spin arrestors, the installation of air breaker/collector vanes withair relief vent, are all geared in achieving a higher degree and widerrange of liquid-solids separation, and elimination ofcavitation-producing air bubbles in the stream.

In one aspect of the invention, the lower open end of the discharge pipehas a bell shape for compressing the downwardly traveling fluids againstthe sides of the chamber, and receiving a wider cross section of theupwardly returning fluid. In another aspect, the lower portion of thecylindrical chamber is enlarged to provide a larger lower annularopening for receiving the solids, and to provide a larger solidssettling area.

In another aspect of the invention, a continuous or disjointed helicalridge is provided along the exterior wall at the lower end of thedischarge tube, instead of the bell-shaped opening. One or more slottedopenings are provided in the wall of the discharge tube adjacent to theridge. The ridge provides a flow path for the incoming fluid stream, andalso a re-entry point for smaller/finer solids from the returning flowstream.

The present invention is most efficient when used to separate and removesolids particles from liquids with a difference in specific gravities of0.75 and greater; and/or to separate liquids of different densities,viscosities, and specific gravities. Known standard separators can onlyeffectively achieve separation down to 60-75 microns with a differentialspecific gravity of 1.0 or greater. The present invention providesimproved separation by removing solids from spherical diameter down toas small as 25 microns, solids with specific gravity as low as 1.75, ora differential specific gravity of 0.75.

It is therefore a primary object of the present invention to provide avortex-based separator for removing solids from a liquid/solids fluidstream in two stages, the first stage using a centrally-located spinplate for reversing the cleaner interior flow of the vortex, and thesecond stage using a plurality of louvered slots in an upper dischargepipe for removing finer solids from the exiting fluid flow.

It is also an important object of the present invention to provideimproved separation of solids from a liquid/solids fluid stream byremoving solids having a spherical diameter as small as 25 microns, withspecific gravity as low as 1.75, or a differential specific gravity aslow as 0.75.

It is a further important object of the present invention to provide avortex-based separator having a plurality of air breaker vanes locatedat the top of the separation chamber which break up, collect andfacilitate removal of entrapped air bubbles to reduce cavitation.

It is a further important object of the present invention to provide avortex-based separator having a plurality of lower arrestor vanesprovided along the interior perimeter of the cylindrical chamber thatstop the solids from spinning on top of the lower spin plate preventingany grinding wear and/or drilling motion that the solids may contribute.

It is a further important object of the present invention to provide avortex-based separator having a set of baffles in the lower collectionchamber to prevent the solids from further spinning and to facilitatequiescent settling of the solids.

Additional objects of the invention will be apparent from the detaileddescriptions and the claims herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of one embodiment of the presentinvention.

FIG. 2 is an isometric partially cut-away view of the embodiment of FIG.1.

FIG. 3 is a partially cut-away side view of the embodiment of FIGS. 1 &2.

FIG. 4 is a sectional view along line A-A of FIG. 3.

FIG. 5 is a sectional view along line B-B of FIG. 3.

FIG. 6 is a sectional view along line C-C of FIG. 3.

FIG. 7 is a sectional view along line D-D of FIG. 3.

FIG. 8 is an enlarged view of the upper portion of the invention shownin FIG. 3.

FIG. 9 is a diagrammatic cut away view showing the operation of theinvention.

FIG. 10 is an enlarged view of the exit pipe of the embodiment of FIGS.1-9.

FIG. 11 is a perspective partially cut-away view of an alternativeembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings wherein like reference characters designatelike or corresponding parts throughout the several views, and referringparticularly to FIG. 2, it is seen that the invention includes a largevessel 21 supported by a set of exterior legs 22, the vessel having acylindrical wall 25 defining an internal chamber 24. A lateral inletpipe 27 is provided near the top of chamber 24 for receiving an incomingfluid stream containing liquid, solids and gasses (“fluid stream”). Anadjustable slot or valve 28 is provided along inlet pipe 27 to vary theflow of the incoming pressure stream. Inlet pipe 27 is attached tovessel 21 in such a way that the fluid flow is introduced into chamber24 at an angle that is generally tangential to cylindrical wall 25, asbest illustrated in FIG. 4. This tangential introduction of fluidresults in a rotational flow inside chamber 24. A central, axiallyaligned exit pipe 29 is provided at the top of vessel 21 leading frominternal chamber 24 to the exterior. An air escape valve 30 is providedat the top of vessel 21, and a solids discharge opening 26 is providedat the bottom of vessel 21, each in communication with interior chamber24.

A plurality of air breaker vanes 31 are provided along the upper edge ofchamber 24 for interrupting the upper portions of the incoming fluidstream to make contact with air bubbles in the fluid stream and directthem toward the top of vessel 21 where they may escape through valve 30.Vanes 31 also provide support and reinforcement for exit pipe 29.

Referring to FIGS. 3, and 7-10 it is seen that a cylindrical sleeve orchoke ring 37 is provided around the lower end of discharge pipe 29,ring 37 having a diameter slightly larger than that of pipe 29. As shownin more detail in FIG. 8, the junction of ring 37 and pipe 29 forms aninternal annular shoulder 38 which restricts the upward flow into pipe29. A continuous or disjointed helical ridge 35 (spiral skirt ring) isprovided around the outside cylindrical edge of ring 37, such that ridge35 protrudes into main chamber 24. A plurality of slotted openings 36are provided in the cylindrical wall of ring 37 in the vicinity of ridge35 as best shown in FIGS. 7 and 9. Openings 36 are preferably angled sothat fluid passing therethrough from inside pipe 29 enters chamber 24 inharmony with the rotational flow established therein. A semi-circularL-shaped flange 19 is provided on the outside of ring 37 adjacent toridge 35 creating a path for receipt of the materials discharged throughangled slots 36. It is to be appreciated that angled openings 36 may beprovided in any suitable locations on ring 37 or on exit pipe 29. In aslight variation of this embodiment, sleeve 37 may be eliminated andridge 35 attached directly to the lower end of exit pipe 29. In thisvariation, angled openings 36 are provided on pipe 29 in the vicinity ofridge 35, and flange 19 may be attached to pipe 29 or it may beeliminated altogether.

In the lower section of chamber 24, a centrally located axially orientedreversing or spin plate 41 is provided. This upper spin plate 41 mayhave a flat surface, or may have a slightly conical shape as illustratedin the drawings. A lower spin plate 42, having a larger diameter thanupper spin plate 41, is provided in chamber 24 below upper spin plate41. Lower spin plate 42 may be flat or concave in shape. Plate 42 isalso centrally located and axially oriented, and defines an annular gap48 between the outer edge of plate 42 and the inside edge of wall 25. Aplurality of upwardly oriented, angled top spin arrestor vanes 45 may beprovided on lower spin plate 42, extending over gap 48 as shown in FIG.5.

The area of chamber 24 below lower spin plate 42 is where solids settleout. A plurality of baffles 49 may be provided in this area, the bafflesextending radially from the center of chamber 24 to the chamber wall 25as shown in FIG. 6. A solids discharge opening 26 is provided belowthese baffles at the bottom of chamber 24.

In an alternative embodiment shown in FIG. 11, the lower cylindricalsection 37 of upper discharge pipe 29 is wider than the remaining pipeforming a bell shape with angled section 38. No helical ridge isprovided in this embodiment, and the slotted openings 36 are provided inlower section 37. It is to be appreciated that openings 36 may beprovided in any or all of sections 29, 37 or 38 of the discharge pipe.The alternative embodiment of FIG. 11 also illustrates a lower chambersection having a wider diameter wall 23 than the main cylinder wall 25.This section holds more solids thereby allowing for more accumulationand hence more time between solids discharge or removal operations.

The operation of the dual stage separator is illustrated in FIG. 9.Initially, a fluid stream containing liquid/solids/gas under pressure isintroduced through inlet opening 27. The fluid flow may be restrictedusing valve 28. The amount of closure of valve 28 is determined by thespecific gravity of the fluid stream introduced. Closing valve 28 causesthe fluid stream to accelerate as it enters the vessel 21 at an anglethat is tangential to cylindrical wall 25, thereby inducing a rotationalflow in chamber 24 around the inside of wall 25 as shown by arrows 51.This flow induces a vortex, pushing the heavier solids outward bycentrifugal force, and leaving a cleaner flow in the center. This mainrotational flow carries the solids down into the vessel 21 along theoutside walls 25. The incoming fluid stream first encounters air breakervanes 31 along the upper edge of chamber 24 which make contact with airbubbles in the fluid stream and directs them toward the top of vessel 21where they may escape through valve 30.

As the helical flow continues downward, it passes between pipe 29 andwall 25, traveling along helical ridge 35. As explained more fullybelow, finer solids are re-introduced into this main flow through slots36 in sleeve 37 or pipe 29 at this time. The main flow travels downwardslowing in speed as it reaches the central portion of chamber 24. Here,the central, cleaner portion of the downward flow encounters upper spinplate 41 which causes this central part of the flow to reverse directionand travel upwards, as shown by arrows 54 of FIG. 9. The outer portionof the flow continues downward according to arrows 51 and nextencounters lower spin plate 42. A plurality of optional angled arrestorvanes 45 may be attached to lower spin plate 42. Vanes 45 interrupt anddirect the solids-laden outer flow through annular opening 48 into thelower portion of chamber 24.

The lower portion of chamber 24 may simply be a large holding area, butis preferably divided into sections by a set of baffles 49 which furtherslow the motion of the fluid entering the lower chamber. It is to beappreciated that any suitable number of baffles may be used dividing thelower chamber into additional sections. The solids are then periodicallyor continuously removed from this quiescent lower chamber throughopening 26.

Meanwhile, the cleaner central flow has reversed direction and spiralsupward toward central discharge tube 29. This flow may still containsome finer solids. A second stage centrifugal separation starts at theentry ring 37 to discharge tube 29 where annular shoulder 38 impedes theencircling smaller solids. A venturi effect is created in the angledopenings 36, drawing these solids through angled slots 36 in ring 37 asa result of the difference in pressure between the high speed incomingflow 51 and the lower speed returning flow 54. Some of the solids aredrawn into a vacuum chamber formed by flange 19 and returned to the maindownward flow. The remaining clean fluid continues upward and exitsvessel 21 through discharge tube 29.

In the alternative embodiment of FIG. 11, as the downward flow passesthe outside of bell-shaped discharge pipe 37-38 it is compressed whichfurther increases velocity, further pushes the main flow toward theoutside walls, and squeezes out (up) trapped air bubbles. The airbubbles travel in an upward direction along the outside wall where theymake contact with air breaker vanes 31 and are released through vent 30.The returning flow 54 enters pipe 37 at a lower speed and is acceleratedby the squeezing action of angled annular flange 38. Angled slots 36 arepreferably provided in the lower pressure section 37 so that anyremaining solids are drawn through the slots by virtue of the largepressure differential between flow 51 and 54 around section 37. However,slots 36 may additionally or alternatively be provided on section 38 andon pipe 29.

It is to be understood that variations and modifications of the presentinvention may be made without departing from the scope thereof. It isalso to be understood that the present invention is not to be limited bythe specific embodiments disclosed herein, but only in accordance withthe appended claims when read in light of the foregoing specification.

1. A centrifugal liquid/solids separator comprising: a. a vessel havinga cylindrical side wall, and upper and lower end walls forming aninterior chamber, said chamber having an upper section and a lowersection; b. an inlet in said cylindrical wall near the upper end wallfor introducing fluid under pressure at an angle that is generallytangential to said cylindrical side wall; c. an outlet pipe axiallymounted in the upper end wall of said vessel, said outlet pipe having acylindrical wall of lesser diameter than said vessel, a hollow interior,an upper portion that extends out from said upper end wall to a firstend, and a lower portion that extends into the upper section of saidchamber to a second end; d. a helical ring attached around thecylindrical wall of said outlet pipe at the second end thereof such thatsaid ring protrudes into the upper section of said chamber; e. aplurality of radially spaced apart axially-extending openings passingthrough the wall of said outlet pipe in the vicinity of said helicalring fluidly interconnecting the interior of said outlet pipe and theupper section of said chamber; and f. a discharge opening in the lowerend wall of said vessel.
 2. The separator of claim 1 wherein a flowrestricting valve is provided in said inlet for increasing the velocityof fluid under pressure introduced through said inlet.
 3. The separatorof claim 2 wherein said flow restricting valve has a parabolic shape. 4.A centrifugal liquid/solids separator comprising: a. a vessel having acylindrical side wall, and upper and lower end walls forming an interiorchamber, said chamber having an upper section and a lower section; b. aninlet in said cylindrical wall near the upper end wall for introducingfluid under pressure at an angle that is generally tangential to saidcylindrical side wall; c. an outlet pipe axially mounted in the upperend wall of said vessel, said outlet pipe having a cylindrical wall oflesser diameter than said vessel, a hollow interior, an upper portionthat extends out from said upper end wall to a first end, and a lowerportion that extends into the upper section of said chamber to a secondend; d. a discontinuous helical ring attached around the cylindricalwall of said outlet pipe at the second end thereof such that said ringprotrudes into the upper section of said chamber; e. a plurality ofradially spaced apart axially-extending openings passing through thewall of said outlet pipe in the vicinity of said helical ring fluidlyinterconnecting the interior of said outlet pipe and the upper sectionof said chamber; and f. a discharge opening in the lower end wall ofsaid vessel.
 5. A centrifugal liquid/solids separator comprising: a. avessel having a cylindrical side wall, and upper and lower end wallsforming an interior chamber, said chamber having an upper section and alower section; b. an inlet in said cylindrical wall near the upper endwall for introducing fluid under pressure at an angle that is generallytangential to said cylindrical side wall; c. an outlet pipe axiallymounted in the upper end wall of said vessel, said outlet pipe having acylindrical wall of lesser diameter than said vessel, a hollow interior,an upper portion that extends out from said upper end wall to a firstend, and a lower portion that extends into the upper section of saidchamber to a second end; d. a helical ring attached around thecylindrical wall of said outlet pipe at the second end thereof such thatsaid ring protrudes into the upper section of said chamber; e. aplurality of radially spaced apart axially-extending openings passingthrough the wall of said outlet pipe in the vicinity of said helicalring fluidly interconnecting the interior of said outlet pipe and theupper section of said chamber; f. an axially oriented circular spinplate of small diameter extending across a portion of said chamber inthe lower section thereof; and g. a discharge opening in the lower endwall of said vessel.
 6. The separator of claim 5 wherein a plurality ofair breaker vanes are provided in the upper section of said chamberextending radially between the cylindrical wall of said vessel and saidoutlet pipe.
 7. The separator of claim 5 wherein the surface of saidspin plate is concave.
 8. A centrifugal liquid/solids separatorcomprising: a. a vessel having a cylindrical side wall, and upper andlower end walls forming an interior chamber, said chamber having anupper section and a lower section; b. an inlet in said cylindrical wallnear the upper end wall for introducing fluid under pressure at an anglethat is generally tangential to said cylindrical side wall; c. an outletpipe axially mounted in the upper end wall of said vessel, said outletpipe having a cylindrical wall of lesser diameter than said vessel, ahollow interior, an upper portion that extends out from said upper endwall to a first end, and a lower portion that extends into the uppersection of said chamber to a second end; d. a helical ring attachedaround the cylindrical wall of said outlet pipe at the second endthereof such that said ring protrudes into the upper section of saidchamber; e. a plurality of radially spaced apart axially-extendingopenings passing through the wall of said outlet pipe in the vicinity ofsaid helical ring fluidly interconnecting the interior of said outletpipe and the upper section of said chamber; f. an axially orientedcircular spin plate having a diameter, said spin plate extending acrossa portion of said chamber in the lower section thereof and defining anannular gap between the edge of said spin plate and the cylindrical wallof said vessel; and g. a discharge opening in the lower end wall of saidvessel.
 9. The separator of claim 8 wherein a plurality of spin arrestorvanes are provided in the lower section of said chamber above said spinplate, extending radially across the annular gap between said spin plateand the cylindrical wall of said vessel.
 10. The separator of claim 8wherein a plurality of baffles are provided in the lower section of saidchamber below said spin plate said baffles extending radially betweenthe center of said chamber and the cylindrical vessel wall.
 11. Theseparator of claim 8 wherein a plurality of spin arrestor vanes areprovided in the lower section of said chamber above said spin plate,extending radially across the annular gap between said spin plate andthe cylindrical wall of said vessel, and wherein a plurality of bafflesare provided in the lower section of said chamber below said spin platesaid baffles extending radially between the center of said chamber andthe cylindrical vessel wall.
 12. The separator of claim 11 wherein aplurality of air breaker vanes are provided in the upper section of saidchamber extending radially between the cylindrical wall of said vesseland said outlet pipe.
 13. The separator of claim 8 wherein a pluralityof air breaker vanes are provided in the upper section of said chamberextending radially between the cylindrical wall of said vessel and saidoutlet pipe.
 14. A centrifugal liquid/solids separator comprising: a. avessel having a cylindrical side wall, and upper and lower end wallsforming an interior chamber, said chamber having an upper section and alower section; b. an inlet in said cylindrical wall near the upper endwall for introducing fluid under pressure at an angle that is generallytangential to said cylindrical side wall; c. an outlet pipe axiallymounted in the upper end wall of said vessel, said outlet pipe having acylindrical wall of lesser diameter than said vessel, a hollow interior,an upper portion that extends out from said upper end wall to a firstend, and a lower portion that extends into the upper section of saidchamber to a second end; d. a helical ring attached around thecylindrical wall of said outlet pipe at the second end thereof such thatsaid ring protrudes into the upper section of said chamber; e. aplurality of radially spaced apart axially-extending openings passingthrough the wall of said outlet pipe in the vicinity of said helicalring fluidly interconnecting the interior of said outlet pipe and theupper section of said chamber; f. a pair of axially oriented circularspin plates of different diameters provided in the lower section of saidchamber; and g. a discharge opening in the lower end wall of saidvessel.
 15. The separator of claim 14 wherein the surface of one of saidspin plates is selected from the group consisting of flat, conical andconcaved; and the surface of the other of said spin plates is selectedfrom the group consisting of flat, conical and concaved.
 16. Acentrifugal liquid/solids separator comprising: a. a vessel having acylindrical side wall, and upper and lower end walls forming an interiorchamber, said chamber having an upper section and a lower section; b. aninlet in said cylindrical wall near the upper end wall for introducingfluid under pressure at an angle that is generally tangential to saidcylindrical side wall; c. an outlet pipe axially mounted in the upperend wall of said vessel, said outlet pipe having a cylindrical wall oflesser diameter than said vessel, a hollow interior, an upper portionthat extends out from said upper end wall to a first end, and a lowerportion that extends into the upper section of said chamber to a secondend; d. a helical ring attached around the cylindrical wall of saidoutlet pipe at the second end thereof such that said ring protrudes intothe upper section of said chamber; e. a plurality of radially spacedapart axially-extending openings passing through the wall of said outletpipe in the vicinity of said helical ring fluidly interconnecting theinterior of said outlet pipe and the upper section of said chamber; f.an upper axially oriented circular spin plate of small diameterextending across a portion of said chamber in the lower section thereof;g. a lower axially oriented circular spin plate having a diameter, saidlower spin plate extending across a portion of said chamber in the lowersection thereof and defining an annular gap between the edge of saidlower spin plate and the cylindrical wall of said vessel; h. a pluralityof air breaker vanes provided in the upper section of said chamberextending radially between the cylindrical wall of said vessel and saidoutlet pipe; i. a plurality of spin arrestor vanes provided in the lowersection of said chamber above said lower spin plate, extending radiallyacross the annular gap between said lower spin plate and the cylindricalwall of said vessel; j. a plurality of baffles provided in the lowersection of said chamber below said lower spin plate said bafflesextending radially between the center of said chamber and thecylindrical vessel wall; and k. a discharge opening in the lower endwall of said vessel.
 17. A centrifugal liquid/solids separatorcomprising: a. a vessel having a cylindrical side wall, and upper andlower end walls forming an interior chamber, said chamber having anupper section and a lower section; b. an inlet in said cylindrical wallnear the upper end wall for introducing fluid under pressure at an anglethat is generally tangential to said cylindrical side wall; c. an outletpipe axially mounted in the upper end wall of said vessel, said outletpipe having a cylindrical wall of lesser diameter than said vessel, ahollow interior, an upper portion that extends out from said upper endwall to a first end, and a lower portion that extends into the uppersection of said chamber to a second end; d. an upper axially orientedcircular spin plate of small diameter extending across a portion of saidchamber in the lower section thereof e. a lower axially orientedcircular spin plate having a diameter, said lower spin plate extendingacross a portion of said chamber in the lower section thereof anddefining an annular gap between the edge of said lower spin plate andthe cylindrical wall of said vessel; and f. a discharge opening in thelower end wall of said vessel.
 18. The separator of claim 17 wherein aplurality of spin arrestor vanes are provided in the lower section ofsaid chamber above said lower spin plate, extending radially across theannular gap between said lower spin plate and the cylindrical wall ofsaid vessel.
 19. The separator of claim 17 wherein a plurality ofbaffles are provided in the lower section of said chamber below saidlower spin plate said baffles extending radially between the center ofsaid chamber and the cylindrical vessel wall.
 20. The separator of claim17 wherein a plurality of air breaker vanes are provided in the uppersection of said chamber extending radially between the cylindrical wallof said vessel and said outlet pipe.
 21. The separator of claim 17wherein a plurality of spin arrestor vanes are provided in the lowersection of said chamber above said lower spin plate, extending radiallyacross the annular gap between said lower spin plate and the cylindricalwall of said vessel, and wherein a plurality of baffles are provided inthe lower section of said chamber below said lower spin plate saidbaffles extending radially between the center of said chamber and thecylindrical vessel wall.
 22. The separator of claim 17 wherein aplurality of spin arrestor vanes are provided in the lower section ofsaid chamber above said lower spin plate, extending radially across theannular gap between said lower spin plate and the cylindrical wall ofsaid vessel, and wherein a plurality of baffles are provided in thelower section of said chamber below said lower spin plate said bafflesextending radially between the center of said chamber and thecylindrical vessel wall, and wherein a plurality of air breaker vanesare provided in the upper section of said chamber extending radiallybetween the cylindrical wall of said vessel and said outlet pipe.
 23. Acentrifugal liquid/solids separator comprising: a. a vessel having acylindrical side wall, and upper and lower end walls forming an interiorchamber, said chamber having an upper section and a lower section; b. aninlet in said cylindrical wall near the upper end wall for introducingfluid under pressure at an angle that is generally tangential to saidcylindrical side wall; c. an outlet pipe axially mounted in the upperend wall of said vessel, said outlet pipe having a cylindrical wall oflesser diameter than said vessel, a hollow interior, an upper portionthat extends out from said upper end wall to a first end, and a lowerportion that extends into the upper section of said chamber to a secondend; d. an upper axially oriented circular spin plate of small diameterextending across a portion of said chamber in the lower section thereofe. a lower axially oriented circular spin plate having a diameter, saidlower spin plate extending across a portion of said chamber in the lowersection thereof and defining an annular gap between the edge of saidlower spin plate and the cylindrical wall of said vessel; f. a pluralityof air breaker vanes provided in the upper section of said chamberextending radially between the cylindrical wall of said vessel and saidoutlet pipe; g. a plurality of spin arrestor vanes provided in the lowersection of said chamber above said lower spin plate, extending radiallyacross the annular gap between said lower spin plate and the cylindricalwall of said vessel; h. a plurality of baffles provided in the lowersection of said chamber below said lower spin plate said bafflesextending radially between the center of said chamber and thecylindrical vessel wall; and i. a discharge opening in the lower endwall of said vessel.
 24. A centrifugal liquid/solids separatorcomprising: a. a vessel having a cylindrical side wall, and upper andlower end walls forming an interior chamber, said chamber having anupper section and a lower section; b. an inlet in said cylindrical wallnear the upper end wall for introducing fluid under pressure at an anglethat is generally tangential to said cylindrical side wall; c. an outletpipe axially mounted in the upper end wall of said vessel, said outletpipe having a cylindrical wall of lesser diameter than said vessel, ahollow interior, an upper portion that extends out from said upper endwall to a first end, and a lower portion that extends into the uppersection of said chamber to a second end said second end having a flaredsection forming a bell shape; d. a helical ring attached around thecylindrical wall of said outlet pipe at the second end thereof such thatsaid ring protrudes into the upper section of said chamber; e. aplurality of radially spaced apart axially-extending openings passingthrough the wall of said outlet pipe in the vicinity of said helicalring fluidly interconnecting the interior of said outlet pipe and theupper section of said chamber; and f. a discharge opening in the lowerend wall of said vessel.
 25. A method for separating solids from aliquid/solids fluid stream comprising the steps of: a. introducing apressurized fluid stream containing solids and liquids into an uppersection of a cylindrical vessel at generally tangential angle to inducea rotational flow inside said vessel; b. pushing the heavier solids insaid fluid stream outward by centrifugal force; c. guiding said fluidstream into a downward spiral using a centrally located helical ridge;d. moving the solids in said downwardly spiraling fluid stream along theinside of the cylindrical vessel to a lower collection chamber in saidvessel; e. reversing the direction of flow of the central portion ofsaid downwardly spiraling fluid stream using an axially oriented centralspin plate causing said central portion to spiral upward; f. receivingsaid upwardly spiraling central portion of said fluid stream into anupper exit pipe that is axially attached at the top of said cylindricalvessel; g. separating finer solids from said upwardly spiraling fluidstream through a plurality of radially spaced apart axially-extendingopenings in said exit pipe, said openings interconnecting the interiorof said exit pipe and the upper section of said vessel; h. dischargingthe remainder of said upwardly spiraling fluid stream through said exitpipe; and i. periodically purging the solids from said lower collectionchamber.
 26. The method of claim 25 comprising the additional step ofnarrowing the upwardly spiraling fluid stream as it enters said exitpipe using an annular choke ring.
 27. The method of claim 25 comprisingthe additional step of restricting the input of said pressurized fluidstream to increase the flow fate inside the vessel.
 28. The method ofclaim 25 comprising the additional steps of separating air bubbles fromthe rotational flow in the upper section of said vessel using aplurality of air breaker vanes adjacent to said input, and periodicallyremoving said separated air using a relief valve.
 29. The method ofclaim 25 comprising the additional steps of interrupting the downwardlyspiraling fluid stream using a plurality of spin arrestor vanes locatedbelow said spin plate and extending radially toward the cylindrical wallof said vessel to stop said rotational flow.
 30. The method of claim 25comprising the additional step of settling said solids using a pluralityof baffles located in the lower section of said vessel.
 31. The methodof claim 25 comprising the additional step of separating finer solidsfrom said upwardly spiraling fluid stream through a plurality ofradially spaced apart axially-extending openings in said exit pipe, saidopenings interconnecting the interior of said exit pipe and the uppersection of said vessel.
 32. A centrifugal liquid/solids separatorcomprising: a. a vessel having a cylindrical side wall, and upper andlower end walls forming an interior chamber, said chamber having anupper section and a lower section; b. an inlet in said cylindrical wallnear the upper end wall for introducing fluid under pressure at an anglethat is generally tangential to said cylindrical side wall; c. an outletpipe axially mounted in the upper end wall of said vessel, said outletpipe having a cylindrical wall of lesser diameter than said vessel, ahollow interior, an upper portion that extends out from said upper endwall to a first end, and a lower portion that extends into the uppersection of said chamber to a second end; d. a helical ring attachedaround the cylindrical wall of said outlet pipe at the second endthereof such that said ring protrudes into the upper section of saidchamber; e. a plurality of openings passing through the wall of saidoutlet pipe fluidly interconnecting the interior of said outlet pipe andthe upper section of said chamber, said openings being provided below aninner annular shoulder of said outlet pipe; and f. a discharge openingin the lower end wall of said vessel.
 33. A centrifugal liquid/solidsseparator comprising: a. vessel having a cylindrical side wall, andupper and lower end walls forming an interior chamber, said chamberhaving an upper section and a lower section; b. an inlet in saidcylindrical wall near the upper end wall for introducing fluid underpressure at an angle that is generally tangential to said cylindricalside wall; c. an outlet pipe axially mounted in the upper end wall ofsaid vessel, said outlet pipe having a cylindrical wall of lesserdiameter than said vessel, a hollow interior, an upper portion thatextends out from said upper end wall to a first end, and a lower portionthat extends into the upper section of said chamber to a second end; d.a helical ring attached around the cylindrical wall of said outlet pipeat the second end thereof such that said ring protrudes into the uppersection of said chamber; e. a plurality of openings passing through thewall of said outlet pipe in the vicinity of said helical ring fluidlyinterconnecting the interior of said outlet pipe and the upper sectionof said chamber; and f. a discharge opening in the lower end wall ofsaid vessel.